| Question | Answer |
| What is the definition of Acute Renal Failure (ARF)? | Sudden decline in the ability of the kidney to maintain fluid and electrolyte homeostasis [Lesser of the following]
Increase of serum Creatinine >=0.3 mg/dL in 48 hours
Increase in serum creatinine >50% in 48 hours. |
| What changes in creatinine define ARF? | [Lesser of the following]
Increase of serum Creatinine >=0.3 mg/dL in 48 hours
Increase in serum creatinine >50% in 48 hours. |
| What might you see clinically in a pt with ARF? | Abrupt onset of:
edema, hematuria, hyper/hypotension, cardiac dysrhythmias, malaise/fatigue, oliguria, altered mental status |
| What are the three types of ARF? | Prerenal
Intrinsic
Postrenal |
| What's up with Prerenal? | Secondary to renal hypoperfusion
Absolute hypovolumemia
Decreased effective arterial blood volume |
| What can cause Postrenal ARF? | Obstructions (stones, masses, blood clot)
[After kidney=tubules, so it must be a blockage] |
| What type of things do you look for in the initial workup of ARF? | Recent illness (medications), new prescriptions, chest pain, SoB, orthopnea, Vomiting/diarrhea, decrease urine output |
| List some potentially nephrotoxic drugs. | ACEI/ARBs
Aspirin
NSAIDs
Gentamicin |
| What co-morbid conditions may contribute to Prerenal ARF? | CHF
Liver Disease
BPH
Coronary artery disease |
| What kind of things might a pt have taken/overdosed? | Methanol
Ethylene glycol
Isopropyl alcohol
Blood pressure pills |
| What physical exam test would you do? | Volume status assessment (BP, HR, mucus membranes, Edema/LVD/Crackles)
Pericardial rub or knock
Signs or otehr predisposing co-morbid conditions. |
| What is the definition of orthostatic hypotension? | Decrease in 20 systolic or 10 diastolic while going from sitting to standing. |
| What physical exam findings would you expect to see in a pt with chronic liver dz and/or cirrhosis? | Jaundice, proteinuria, haptomegaly, gynecomastia, caput medusa, small testicles |
| What things would you do at the pts bedside? | Bladder scan (pre and post-void)[small change or ~300mL post-void may point to obstruction)
Insert Foley Cath
Strictly record fluid input and output |
| What labs would you order? | Urinalysis, which includes:
Specific gravity, Urine osmolaoity, casts, hematuria, and proteinuria |
| If a pt has high SpGr, what would you expect the Uosm to be? | High Usom |
| How do we calculate FeNa? | FeNa= (Una*Serum Cr)/(Serum Na*Una)*100 |
| When do you use FeUr instead of FeNa? | If the pt is taking a diuteric |
| What will you see in FrNa and FeUr for Prerenal dz? | FeNa<1%
Fe Ur <35% |
| What will you see in FrNa and FeUr for Intrinsic dz? | FeNa>2%
Fen > 50% |
| What are you looking for on renal ultrasound? | Size
Echogenicity
Presence/absence of hydronephrosis
Nephrolithiasis
Number of Kidneys |
| True/False
ARF cna be defined as an increase in serum creatintine >25% in 48 hours. | False, it's an increase >50% in 48 hours. |
| List some possible causes of Postrenal ARF. | BPH
Kidney stones/blood clots
Pelvic Malignancy
Lymphoma (predisposes to retroperitoneal fibrosis)
Neurogenic bladder |
| How do you make the Dx of postrenal ARF? | 1. Obtain pre/post-void residuals using bladder scan and place Foley catheter
2. Renal ultrasound
3. Prostate Exam |
| How do you treat postrenal ARF? | 1. Treat the underlying cause
2. Foley cath placement imperitive
3. May require urological intervention |
| What's the prognosis for postrenal ARF? | It's typically favorable as long as the acute obstruction is relieved within ONE WEEK |
| True/False
Postrenal obstruction should be sispected in pts who report recently passing of clots. | True |
| What volume in a post-void bladder makes you suspicious of postrenal ARF? | >300 ccs |
| True/False
Postrenal obstruction can be ruled out if <=300 ccs of urine are seen on post-void bladder scan | False |
| What's the etiology of prerenal ARF? | Lack of kidney fxn (occurs if MAP <60)
Kidney essentially starved of blood |
| What in a pts Hx would make you suspect prerenal ARF? | If they have absolute or effective hypovolemia. |
| List some causes of Absolute hypovolemia. | Dehydration
No access to water
Excessive diuresis
GI bleed or other hemmorrhage |
| Name some causes of Effective hypovolemia. | Decreased circulating volume
CHF
Advanced Liver Disease
Septic Shock
Cardiac Tamponade |
| What are some physical exam findings you'd see with prerenal ARF? | Low/low-normal BP
Orthostatic hypotension
Tachycardia
Dry mucus membranes |
| What lab values would you see in a pt with prerenal ARF? | BUN/Cr ratio >=20:1
Increased SpGr on Ua (>1.025)
Increased Uosm (>500)
FeNa <1% or FrUr <35% |
| What is the Tx for Prerenal ARF? | Treat underlying cause
Stop all BP meds, especially ACEI/ARBs
Stop diuretics
Volume resuscitation with normal saline |
| What would extended Tx involve? | Frequent BP checks
Strict monitoring of ins & outs
Repeat physical for volume status
Daily BMP to trend creatintine |
| True/False
A BUN/Cr ratio of >= 20:1 supports the Dx of prerenal ARF. | True |
| True/False
Prerenal ARF can be ruled out in patients who appear to be volume overloaded. | False |
| True/False
Uosm and specific gravity should be decreased in pts with prerenal ARF | False
Sp Gr is increase (>1.025) and Uosm is high (>500) |
| True/False
ARF in a common finding in a hospitalized pt. | True |
| Name some of the initial work-up for a pt with ARF | Foley cath
bedside bladder scan
UA, Uosm, FeNa/FeUr
Renal ultrasound |
